蛋氨酸脑啡肽对疟疾感染鼠一氧化氮产生的研究

探讨蛋氨酸-脑啡肽(M-ENK)对约氏疟原虫感染早期小鼠脾细胞分泌一氧化氮(NO)的免疫调节效应及相关机制。以不同浓度的M-ENK(单独或与LPS合用)与疟原虫感染后第3dBALB/c或DBA/2小鼠的脾细胞共同培养,通过Griess反应和ELISA法分别检测其上清中NO和IFN-γ的水平。脾细胞与浓度为10-10或10-11mol/L的M-ENK培养后,NO的分泌水平明显升高,并且与LPS联合刺激后其NO的产生进一步增强,但IFN-γ水平均未出现有意义的变化。提示浓度为10-10或10-11mol/L的M-ENK能够促进约氏疟原虫感染小鼠脾细胞NO的产生,该作用与IFN-γ活化巨噬细胞路径可能无关,同时M-ENK对LPS的刺激效应也具有强化作用。     

BALB/c小鼠感染不同疟原虫CD4＋ Th应答和凋亡特点的比较研究

探讨不同疟原虫感染BALB/c小鼠的免疫应答特点。BALB/c小鼠经腹腔注射致死型约氏疟原虫（P.y17XL）和夏氏疟原虫（P.cAS）感染的红细胞,计数红细胞感染率;ELISA动态检测感染小鼠脾细胞培养上清中IFN-γ和IL-4水平;流式细胞术检测脾中CD4＋T细胞凋亡数量。约氏疟原虫（P.y17XL）感染早期,小鼠原虫血症持续上升;IFN-γ和IL-4分泌水平仅在感染后第3天出现一过性有意义的升高,而且峰值较低;脾中CD4＋T细胞大量凋亡,小鼠全部死亡;而夏氏疟原虫（P.cAS）感染小鼠,原虫血症上升缓慢;IFN-γ分泌水平在感染后第5天达峰值;IL-4分泌水平在感染后第10天达峰值,且峰值较高维持时间较长;脾中CD4＋T细胞凋亡细胞于感染后8 d出现有意义升高,小鼠全部存活。抗疟保护性免疫有赖于Th1和Th2型免疫应答的有效建立和协调过渡,感染期间CD4＋T细胞凋亡的时相和数量可能是影响免疫应答的强度或引起宿主免疫抑制的原因,从而影响宿主疟原虫感染的结局。     

雪灵芝粗多糖对小鼠免疫细胞增殖与功能的体外激活作用

为观察雪灵芝粗多糖(Arenaria kansuensis crude polysaccharide,AKCP)对体外培养的小鼠脾淋巴细胞、NK细胞和腹腔巨噬细胞增殖与功能的影响。以不同浓度AKCP作用于体外培养的上述细胞48 h,采用中性红吞噬实验及NO释放实验检测巨噬细胞功能,MTT法检测脾淋巴细胞增殖及NK细胞杀伤活性,流式细胞术检测脾淋巴细胞CD3~+、CD4~+、CD8~+亚群,ELISA法检测脾细胞培养上清中IL-2和IFN-γ水平。结果显示,AKCP各浓度组小鼠腹腔巨噬细胞的吞噬活性和NO释放量、脾淋巴细胞刺激指数及培养上清中IFN-γ水平、NK细胞杀伤活性均高于空白对照组(P0.05);AKCP中浓度组脾淋巴细胞CD3~+、CD4~+亚群及培养上清中IL-2水平也明显升高(P0.05)。提示AKCP对小鼠免疫细胞的增殖与功能具有体外激活作用。     

Tim-1分子在约氏疟原虫感染模型中的表达分析

Tim-1分子表达在T细胞和调节性B细胞表面,具有促进Th2应答的作用。为探讨Tim-1分子在抗疟疾免疫应答中的作用,利用致死型约氏疟原虫(Plasmodium yoelii)感染鼠疟模型研究了Tim-1分子表达与小鼠感染结局和免疫应答模式的关系。结果显示,BALB/c小鼠对P.yoelii易感,在感染后6～7 d全部死亡,感染后第3、5天脾内细胞因子IFN-γmRNA水平明显低于对P.yoelii抵抗的DBA2小鼠,而脾IL-10 mRNA水平显著高于DBA2小鼠。BALB/c小鼠脾内Tim-1+T、B细胞百分比在感染后第3、5天显著升高,而DBA2小鼠感染前后脾内Tim-1+T、B细胞百分比没有显著变化。结果提示,Tim-1分子参与抗P.yoelii免疫应答的调节,可能与易感鼠产生高水平Th2型细胞因子有关。     

金线莲多糖对免疫抑制小鼠脾淋巴细胞体外增殖、分泌NO及细胞因子的影响

本试验旨在研究金线莲多糖(ARP)对免疫抑制小鼠脾淋巴细胞体外增殖、NO及细胞因子IL-2、IL-6、IFN-γ分泌水平的影响。MTT法检测小鼠脾淋巴细胞体外增殖;Griess法检测NO分泌水平;ELISA法检测细胞因子IL-2、IL-6、IFN-γ的含量。结果显示,与对照组比较,ARP在50~400μg/m L可明显促进免疫抑制小鼠脾淋巴细胞体外增殖(P0.01),促进NO分泌(P0.01),促进细胞因子IL-2、IL-6和IFN-γ分泌(P0.05,P0.01)。以上结果提示ARP能提高免疫抑制小鼠脾淋巴细胞体外免疫活性,其作用机制可能与促进免疫抑制小鼠脾淋巴细胞增殖,促进NO产生以及提高IL-2、IL-6、IFN-γ的分泌水平有关。     

大蒜素对致死型约氏疟原虫鼠疟模型CD4+活化/凋亡T细胞的影响

探讨大蒜素对致死型约氏疟原虫(Plasmodium yoelii 17XL,P.y 17XL)感染BALB/c小鼠T细胞免疫应答的影响。P.y 17XL感染后第0~2天每日口服给予不同浓度大蒜素(3 mg/kg或9 mg/kg)处理;动态监测各组小鼠原虫血症水平和生存期;感染后第0天、第3天和第5天无菌提取小鼠脾细胞,FACS检测小鼠活化T细胞(CD4~+CD69~+)、凋亡CD4~+T细胞(7AAD~-Annexin V~+)数量变化;ELISA检测脾细胞培养上清中IFN-γ和TNF-α的水平。结果显示:与NC组相比,大蒜素处理组能降低感染小鼠的原虫血症水平,延长生存期。大蒜素处理能提高感染小鼠活化T细胞的数量,降低凋亡T细胞数量,并能提高脾细胞培养上清中IFN-γ和TNF-α的水平。大蒜素能在感染早期促使宿主建立有效的Th1免疫应答,从而抑制红内期P.y 17XL疟原虫感染进程。     

乙肝疫苗新型佐剂 CpG-BW006对小鼠脾 NK 细胞表面分子 CD69的表达及γ干扰素分泌的影响

目的:研究重组乙型肝炎表面抗(HBsAg)佐剂 BW006对小鼠脾自然杀伤(NK)细胞表面分子 CD69的表达和γ干扰素(IFN-γ)分泌水平的影响.方法:BW006、HBsAg 单用或联用体外刺激小鼠脾 NK 细胞,流式细胞仪检测NK 细胞膜表面分子 CD69的表达水平,ELISA 检测 IFN-γ的分泌水平.结果:5μg BW006体外刺激小鼠脾 NK 细胞24 h 后,NK 细胞表面分子 CD69的表达达峰值(阳性率45.18%),显著高40μg HBsAg 组(21.44%)(P<0.05),与5μg BW006和40μg HBsAg 联用组(58.49%)相比无显著差异;24 h 时,5μg BW006组的 IFN-γ分泌水平达56.95 ng/mL,显著高40μg HBsAg 组(8.74 ng/mL)(P<0.05),与联用组(57.70 ng/mL)相比无显著差异.结论:BW006具有上调 NK 细胞表面分子 CD69表达和诱导 IFN-γ分泌的早期活化 NK 细胞的功能,作为疫苗的新型佐剂前景较好.     

不同毒力疟原虫感染早期根治性治疗对免疫记忆形成影响的研究

为探讨不同毒力疟原虫感染早期根治性治疗对免疫记忆形成的影响,用致死型和非致死型约氏疟原虫感染DBA/2小鼠,感染后3 d进行根治性治疗,并于初次感染后90 d进行再感染。通过计数红细胞感染率和检测再感染前后不同时间点脾细胞中记忆性T、B细胞的百分含量后发现,再感染后2组小鼠均出现了短暂的低水平虫体血症;再感染前小鼠脾细胞中记忆性T、B细胞百分率均略高于正常鼠;但再感染后均出现了有意义的升高;在每一相同检测时间点,2组小鼠的虫体血症水平和记忆性T、B细胞百分率均无显著差异。这表明,不同毒力疟原虫感染早期的根治性治疗可使宿主产生水平相近的免疫记忆,再感染可促进免疫记忆的形成。     

TLR4激活剂对约氏疟原虫感染早期免疫应答的影响

通过外源性给予LPS,探讨TLR4在疟疾感染早期免疫应答的作用特点及其免疫调节作用。通过Plasmodium yoelii 17XL感染的BALB/c小鼠建立鼠疟模型并在感染前给予LPS,于感染第0、3和5天制备脾细胞悬液,通过流式细胞术检测脾细胞悬液中TLR4+DCs和Tregs百分含量;ELISA方法检测脾细胞培养上清中IFN-γ和IL-10水平。结果显示,LPS处理能够显著延长宿主生存期,降低原虫血症水平,同时显著提升脾上清中的IFN-γ水平,降低抑炎性细胞因子IL-10水平。在感染早期,LPS处理可诱导Th1型免疫应答的有效建立,明显遏制P.y 17XL红内期疟原虫的感染进程。     

血吸虫感染通过抑制前炎症免疫应答缓解实验性脑疟的发生

脑疟所引起的严重神经系统的并发症是引起5岁以下儿童死亡的主要原因。疟疾宿主体内免疫应答紊乱是引起脑疟发生的重要机制。目前在疟疾流行区,疟疾患者常常伴有蠕虫感染,但感染虫株类型,严重程度以及感染途径不同均会影响感染结局。为探讨前炎症免疫应答在混合感染中的作用地位,采用日本血吸虫和ECM模型来探讨相关免疫机制。通过建立混合感染模型,监测原虫血症水平和宿主生存期;FACS检测脾脏中DC亚群、巨噬细胞、Treg以及相关功能分子CD86、TLR4、TLR9的表达水平;ELISA和Griess法检测脾细胞培养上清中IL-10、TNF-α、IFN-γ和NO的分泌水平。日本血吸虫感染增加ECM小鼠体重,降低原虫血症,延长小鼠生存期。混合感染抑制ECM模型小鼠脾脏DC亚群和巨噬细胞的数量,TLR9的表达水平也显著降低。ELISA和Griess检测结果显示混合感染显著降低ECM前炎症细胞因子TNF-α、IFN-γ和NO的表达水平,同时增加Treg的数量和IL-10的表达水平。结果表明,日本血吸虫感染会通过抑制前炎症免疫应答来缓解ECM的发生,从而延长宿主生存期。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.